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Phi2 Lupi, HD136664, HIP75304, HR5712

Phi2 Lupi is a blue main sequence dwarf star that can be located in the constellation of Lupus. Phi2 Lupi is the brightest star in Lupus based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Phi2 Lupi is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR5712. HIP75304 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD136664.

Location of Phi2 Lupi

The location of the star in the galaxy is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The Right Ascension is how far expressed in time (hh:mm:ss) the star is along the celestial equator. If the R.A. is positive then its eastwards. The Declination is how far north or south the star is compared to the celestial equator and is expressed in degrees. For Phi2 Lupi, the location is 15h 23m 09.36 and -36d 51` 30.4 .

Proper Motion of Phi2 Lupi

All stars like planets orbit round a central spot, in the case of planets, its the central star such as the Sun. In the case of a star, its the galactic centre. The constellations that we see today will be different than they were 50,000 years ago or 50,000 years from now. Proper Motion details the movements of these stars and are measured in milliarcseconds. The star is moving -20.72 ± 0.10 miliarcseconds/year towards the north and -18.24 ± 0.20 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Phi2 Lupi

Phi2 Lupi has a spectral type of B4V. This means the star is a blue main sequence dwarf star. The star is 7264.00000000 Parsecs from the Galactic Centre or terms of Light Years is 23692.5053081600000000s. The star has a B-V Colour Index of -0.15 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 13,674 Kelvin.

Phi2 Lupi Radius has been calculated as being 3.83 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,664,492.17.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 3.27. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

Phi2 Lupi Apparent and Absolute Magnitudes

Phi2 Lupi has an apparent magnitude of 4.54 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. If you used the 1997 Parallax value, you would get an absolute magnitude of -1.81 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.47. Magnitude, whether it be apparent/visual or absolute magnitude is measured by a number, the smaller the number, the brighter the Star is. Our own Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.

Distance to Phi2 Lupi

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 5.38 which gave the calculated distance to Phi2 Lupi as 606.25 light years away from Earth or 185.87 parsecs. It would take a spaceship travelling at the speed of light, 606.25 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

In 2007, Hipparcos data was revised with a new parallax of 6.28 which put Phi2 Lupi at a distance of 519.37 light years or 159.24 parsecs. It should not be taken as though the star is moving closer or further away from us. It is purely that the distance was recalculated.

The star's Galacto-Centric Distance is 7,264.00 Parsecs or 23,692.51 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Source of Information

The source of the information if it has a Hip I.D. is from Simbad, the Hipparcos data library based at the University at Strasbourg, France. Hipparcos was a E.S.A. satellite operation launched in 1989 for four years. The items in red are values that I've calculated so they could well be wrong. Information regarding Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

Phi2 Lupi Facts

Alternative Names

Bayer DesignationPhi2 Lupi
Hipparcos Library I.D.75304
Yale Bright Star Catalogue (HR) Id5712
Henry Draper Designation136664

Visual Facts

Star Typemain sequence dwarf star
Absolute Magnitude-1.81 / -1.47
Visual / Apparent Magnitude4.54
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)15h 23m 09.36
Declination (Dec.)-36d 51` 30.4
Galactic Latitude16.75 degrees
Galactic Longitude333.84 degrees
1997 Distance from Earth5.38 Parallax (milliarcseconds)
 606.25 Light Years
 185.87 Parsecs
2007 Revised Distance from Earth6.28 Parallax (milliarcseconds)
 519.37 Light Years
 159.24 Parsecs
Galacto-Centric Distance23,692.51 Light Years / 7,264.00 Parsecs
Proper Motion Dec.-20.72 ± 0.10 milliarcseconds/year
Proper Motion RA.-18.24 ± 0.20 milliarcseconds/year
B-V Index-0.15
Radial Velocity0.80 ± 2.70 km/s
Spectral TypeB4V
Associated / Clustered StarsPhi1 Lupi
Colour(B) blue

Estimated Facts

Calculated Effective Temperature13,674 Kelvin

Sources and Links

SIMBAD SourceLink

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